[ARC5] GO-9, ATC, ATD, RAX-1, ARB Remarks

[Mike Morrow]

Gene wrote:

> My ATD has the following tuning units...
> 200-540 KC
> 540-1,500 KC
> 1,500-3,000 KC
> 3,000-9,050 KC
>
> I think this was a very standard config from what I have gathered...

In contrast to your list, the ATD was supplied from Bendix with *no* 
CRR-47207 200-540 kHz tuning unit and with *two* CRR-47210 3000-9050
tuning units.  The ATD manual of 4 AUG 43 ( http://aafradio.org/docs/ATD.pdf )
says that the ATD is provided with those four, but states that one for 
200-540 kHz and one for 9050-15800 kHz are available.  Later the manual
states that information on these last two units is provided "in the event
that these units are made available to the service at some subsequent date."
Definitely, the 200-540 kHz unit was.

What doesn't make a lot of sense was providing the CRR-47206 antenna tuning
unit for 200-540 kHz, but no CRR-47207 transmitter tuning unit for that range.
The CRR-47208 540-1500 kHz tuning unit was provided instead.  I suspect
that some delay in production was responsible for the lack of the CRR-47207.
The inclusion of two CRR-47210 units make perfect sense since that allows two
channels to be preset in that range.  That's still pretty limited, but it's
a lot better than having only one preset channel in that most important
3000-9050 kHz range. 

Dave wrote:

> I have an ATD in the winter project que.
> Probably going to pair it with RAX.

There's a mid-WWII USN training manual that has a section in the back that
lists the radio equipment on most USN aircraft.  In every instance, the ATD
has the ARB is its companion.  Mike Hanz has a copy of this section at 
 http://aafradio.org/docs/Navy-radio-gear-1943.pdf .  The RAX-1 seems 
associated only with the GO-9.  The ARB/ATD/ZB-*/LM-* combo is a perfect 
contemporary radio technology match-up!

Which brings up another remarkable item.  In this 1943 training document
there is *no* listing for the Collins ATC.  The ATD shows up in four places
and the ATC in none. I've always doubted that the ATC was available until
the late-1943 to early-1944 era.  Its omission in this 1943 listing lends
some evidence for that.  I don't believe there's any likelihood that the
ATC was deployed in 1942, or even by mid-1943.

It's likely that the listed aircraft actually wound up with the ATC instead
of the ATD, once it was finally available.  The ATC replaced the GO-9 in
many places as well.

73,
Mike / KK5F